The semiconductor industry has experienced rapid growth and demands for highly integrated semiconductor devices are increasing. Technological advances in integrated circuit (IC) design and materials have produced generations of ICs. Each generation has smaller and more complex circuits than previous generations.
In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometric size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased. This scaling-down process generally provides benefits by increasing production efficiency and lowering associated costs. However, challenges from both fabrication and design issues have resulted in the development of three-dimensional designs, such as the fin field effect transistor (FinFET). Advantages of these transistors may include reducing the short channel effect and increasing the current flow.
Although existing FinFETs and methods of fabricating those transistors have been generally adequate for their intended purposes, they have not been entirely satisfactory in all respects.